To truly appreciate the impact of Kenny Vaccaro, you have to appreciate his mindset.

He sees himself as the best. Yet you can see the giant chip on his shoulder. Always something to prove.

He sees himself as a guy who holds himself to the highest standard. And he doesn't understand those who don't do the same.

As a result, his personality is often interpreted as arrogant, self-important or high maintenance.

One NFL agent told me, "Vaccaro can play. He gives up his body. He plays physical. He can cover the slot, because he has great speed. Every defense needs a guy like him in the secondary because of that versatility.

"But he has to be careful not to think he's better than he is. I think someone will take him in the first round, so we'll see how he handles coming into a bunch of money. Money makes you more of what you are - either good or bad.

"But every coach in the NFL wants a guy who plays the way Vaccaro plays because you can see he loves the game and plays physical."

The bottom line is Vaccaro could have shut it down after the OU game, when it was clear Texas had major problems to solve. He didn't. He could have put it on cruise control. He didn't.

Instead, he kept giving it everything he had and challenged others to do the same. Vaccaro finished 2012 with a team-leading 104 tackles after posting 82 in 2011, and the opponent felt the force of most every one of them.

Vaccaro has come under some scrutiny this season for not doing enough to help the defense.

I find that ridiculous.

The blame for this year's failures rest squarely on Manny Diaz and his inability to develop the LB position. The breakdowns at the LB level were at least 75 percent of the problems on D this year.

When breakdowns at that level occur, the trust from the secondary in the LBs goes out the window, and everyone looks bad.

Vaccaro was NOT the problem this year. Good heavens. They had him doing everything to patch the holes. He was great in coverage this year and led the team in tackles.

Watch the film of the Alamo Bowl against Oregon State's 1,000-yard receivers Markus Wheaton and Brandin Cooks.

Vaccaro's physical play off the line taking away those short, crossing routes was the reason the ball never got out and the rush got home so many times.

Vaccaro was the unsung hero of the game.

Against Kansas, they moved him from nickel to a hybrid LB position in the second half and just told him to clean everything up, and he did.

If you're complaining about some missed tackles in the stretch of Ok St-OU, it was because no one on D could believe how bad things got at LB after Jordan Hicks went down.

But after OU, when Vaccaro stood up in the locker room and told everyone to prepare for war in practice to get tougher, the defense followed he and Okafor into battle.

One of Manny Diaz's biggest sins this year was sticking too long with Cobbs and Steve Edmond. Diaz should have played Jinkens and Jackson much earlier at OLB. And Diaz should have gone with Kendall Thompson much more at MLB.

But to blame Vaccaro for this mess is blind foolishness.

Vaccaro's leadership is classic "in-your-face" leadership. He's not going to spend a lot of time holding guys' hands. He's going to light people up and say, "That's how you do it."

Lamarr Houston and Sergio Kindle led by their actions and physical play when Vaccaro was a pup. Vaccaro respected that those guys just made a ton of plays and didn't say much. That's how Vaccaro leads on the field.

Replacing that thumping play-making and swagger will be difficult. And that brings us to Quandre Diggs.

When I look at the defense, Diggs is the only guy coming back with skins on the wall who is a proven leader. And that's why he may end up at safety next season.

The defense needs someone who can line up the defense, make calls with authority, make plays with authority and provide some swagger in the back end.

Diggs is that guy right now.

Carrington Byndom took a step back this season. After posting 58 tackles in 2011 with 15 pass breakups and 17 passes defended, Byndom had 54 tackles with just 6 pass breakups and 9 passes defended in 2012.

Diggs led the team in interceptions in 2011 with 4 and did so again in 2012 with 4 and increased his tackles from last year (51) to this year (59).

The coaches know Byndom can play well at corner, because he did it in 2011.

The coaches are high on sophomore-to-be Duke Thomas at corner. He should have played more this season. Period.

If Byndom and Thomas can take big steps this off-season, the best four defensive backs on the field to start next season appear to be Byndom and Thomas at corner with Diggs and either Phillips, Mykkele Thompson, Josh Turner or redshirt freshman Adrian Colbert at safety.

Diggs said at the Alamo Bowl he's a team player and will do whatever the team needs of him. What the team needs is an ass-kicker at safety on par with Vaccaro. Someone who will make plays while playing physical. Someone respected by the entire locker room, who loves the game. Someone who jumps out on film to opposing offenses.

And right now, the only player you see that comes close to the job description or replacing Vaccaro is Diggs.